A method that uses a microphone array for spatially selective sound pickup during an audio-video recording session is described. An audio signal for the audio-video recording session is generated using a beamforming process from the microphone array in accordance with a sound pickup directivity pattern. Ambient sound pressure level of the audio-video recording session is monitored while generating the audio signal. The sound pickup directivity pattern of the beamforming process is automatically adjusted during the audio-video recording session as a function of the monitored ambient sound pressure level. Other embodiments are also described and claimed.
Legal claims defining the scope of protection, as filed with the USPTO.
1. A method of using a microphone array for spatially selective sound pickup during an audio-video recording session, the method comprising: generating, using a beamforming process, an audio signal for the audio-video recording session from the microphone array in accordance with a sound pickup directivity pattern; monitoring ambient sound pressure level of the audio-video recording session while generating the audio signal; and automatically adjusting the sound pickup directivity pattern of the beamforming process during the audio-video recording session as a function of the monitored ambient sound pressure level.
2. The method of claim 1 , wherein a low directivity pattern is used for the beamforming process when the monitored ambient sound pressure level is below a first sound level threshold and a high directivity pattern is used for the beamforming process when the monitored ambient sound pressure level is above a second sound level threshold.
3. The method of claim 2 , wherein the first sound level threshold is the same as the second sound level threshold.
4. The method of claim 2 , wherein the first sound level threshold is lower than the second sound level threshold.
5. The method of claim 2 , wherein the low directivity pattern has a directivity index that is less than 4.8 dB.
6. The method of claim 5 , wherein the high directivity pattern has a directivity index that is equal to or greater than 4.8 dB.
7. The method of claim 2 , wherein the low directivity pattern is omnidirectional or sub-cardioid, and the high directivity pattern is a cardioid, super-cardioid, or hyper-cardioid.
8. The method of claim 1 further comprising automatically adjusting white noise gain (WNG) of the beamforming process during the audio-video recording session as a function of the monitored ambient sound pressure level.
9. The method of claim 8 , wherein a strict WNG constraint is used when the monitored ambient sound pressure level is below a third sound level threshold and a loose WNG constraint is used when the monitored ambient sound pressure level is above a fourth sound level threshold.
10. The method of claim 9 , wherein the third sound level threshold is lower than the fourth sound level threshold.
11. The method of claim 1 , wherein the function maps higher ambient sound pressure levels to higher directivity indexes for the sound pickup directivity pattern of the beamforming process.
12. A handheld device comprising: a camera that is to record video; a microphone array that is to capture audio; a sound level monitor that is to monitor ambient sound pressure level; and an audio processor that is to generate, using a beamforming process, an audio signal from the microphone array in accordance with a sound pickup directivity pattern, and to automatically adjust the sound pickup directivity pattern of the beamforming process as a function of the monitored ambient sound pressure level.
13. The handheld device of claim 12 , wherein the audio processor adjusts the sound pickup directivity pattern of the beamforming process by adjusting a directivity index of the sound pickup directivity pattern based on the monitored ambient sound pressure level.
14. The handheld device of claim 12 , wherein a low directivity pattern is used for the beamforming process when the monitored ambient sound pressure level is below a first sound level threshold and a high directivity pattern is used for the beamforming process when the monitored ambient sound pressure level is above a second sound level threshold.
15. The handheld device of claim 14 , wherein the audio processor further is to automatically adjust white noise gain (WNG) of the beamforming process as a function of the monitored ambient sound pressure level.
16. The handheld device of claim 15 , wherein a strict WNG constraint is used when the monitored ambient sound pressure level is below a third sound level threshold and a loose WNG constraint is used when the monitored ambient sound pressure level is above a fourth sound level threshold.
17. A method of using a microphone array for spatially selective sound pickup during an audio-video recording session, the method comprising: generating, using a beamforming process, an audio signal for the audio-video recording session from the microphone array in accordance with a sound pickup directivity pattern; monitoring ambient sound pressure level of the audio-video recording session while generating the audio signal; and automatically adjusting white noise gain (WNG) of the beamforming process as a function of the monitored ambient sound pressure level.
18. The method of claim 17 , wherein a strict WNG constraint is used when the monitored ambient sound pressure level is below a first sound level threshold and a loose WNG constraint is used when the monitored ambient sound pressure level is above a second sound level threshold.
19. The method of claim 18 , wherein the first sound level threshold is the same as the second sound level threshold.
20. The method of claim 18 , wherein the first sound level threshold is lower than the second sound level threshold.
Cooperative Patent Classification codes for this invention. Click any code to explore related patents in that topic.
August 4, 2014
April 26, 2016
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